Ecological Energetics, Hierarchy, and Urban Form: A System Modelling Approach to the Evolution of Urban Zonation

Cities are hierarchical centers of consumption and have had sharp pulses of growth and decline over history. Viewing regional development from an energy perspective is appealing in its analogy to natural systems, though the theory itself as applied to social systems remains undeveloped. The evolutionary changes of an urban system are strongly determined by exogenous energetic inputs and internally self-organized behaviors. Energy from life-support and production systems transformed and is converged spatially to urban centers. The energy-systems language method has kinetic and energetic definitions to represent open thermodynamics and the equations for simulation. This method is applied to study the evolution of urban ecosystems. Ideas of systems ecology and energetic hierarchy emerging from general system theory are adapted to formulate a macro evolutionary model of urban zonal systems. Five consecutive zones are proposed to represent Taipei metropolis: undeveloped; agricultural; residential; industrial; and urban. Each zone includes variables of area, asset, and population, and pathways interconnecting system components. Left – right positions of each zone indicate places in energy hierarchy with power circuits from left to right linking different zones, and control circuits from right to left. A model of urban zonation formulated as a set of differential equations is developed. The model is run to assess the evolution of urban zones in relation to energetic flows. Over time each zone within the urban system of Taipei metropolis evolves as a result of energy convergence and is forced to adapt its internal structure in response to external changes. Similar to care in ecosystems, it is concluded that urban systems exhibit in the long run a certain morphogenesis, a qualitative change in dynamics which moves an urban system toward different stages of spatial organization.